Hi guys, love the game and i have played it since the browser free beta!
I have now bought the Android version, and like a lot of other people here found a few things unrealistic/annoying. E.g. The not enough bridges problem.

But at the end I see and understand the struggle for the developers to balance a game with enough advanced features for experts and realists, but keep it simple enough for beginners and casuals.

My suggestion is to add a new game mode for those that like a more realistic gameplay. So you can keep a simple game mode for beginners, and a more complex one for the experts.

A feature which I’d like to see in the new game mode would be money to buy upgrades at the end of each day, rather than being randomly offered 2.

How could it work?

You gain money for each passenger that travels on your metro.

After each day you are given the option to spend the money on upgrades… Not randomly selected, but any upgrade you like. (this way a player can choose what he actually needs, rather than hope for chance).

No longer will the player be given a locomotive after each day, instead they’ll have to buy it.

Other possible features that work with money:

Each line has a base cost to run per day.
The more engines on a line, the more expensive that line becomes to run, the same apply to carriages. (This could be used to counter-act the huge influx of money at the later half of the game where they usually get flooded with metro users.)

New ranking systems based on money, total profit, balance at the end etc…

Could create new conditions for game over, such as going bankrupt. (it is suggested that bankrupcy is considered when player has negative balance and makes a loss 2 days in a row).

If your goal is realism, you might consider that most public transit systems operate at huge losses. The New York subway and London Tube both operate at loss, and while it’s a bit harder to say about the Shinkansen it is probably just closer to even.

So if you want financial realism for your mini metro, you would want to factor in that you get most of your money from the government, not from your own revenue. Of course, government funds are often earmarked for specific projects, so even though you want to build a bridge the taxpayers might just hand you cash that can only buy a locomotive without asking you.